1. Technical Field
The present invention relates to a liquid crystal display device and an electronic apparatus.
2. Related Art
As research and development for improving quality and performance of a liquid crystal display device, technologies of widening a viewing angle of the liquid crystal display device are studied. Among them, an in-plane switching (IPS) method of generating an electric field in a substrate in an in-plane direction (horizontal direction) and rotating liquid crystal molecules in the plane parallel to the substrate by the electric field in the horizontal direction so as to control transmitted light is put to practical use. In addition, a fringe-field switching (FFS) method which is an improvement of the IPS method is suggested.
FIG. 11 is a schematic view showing the FFS method, wherein FIG. 10A shows the shape of liquid crystal when the electric field is not generated and FIG. 11B shows the shape of the liquid crystal when the electric field is generated. In the FFS method, liquid crystal molecules 302 are interposed between a pair of substrates 300 and 301 and the liquid crystal molecules 302 are driven by the electric field E generated by a pair of electrodes 303 and 304 provided on one substrate with an insulating layer 305 interposed therebetween. When the electric field E is not generated, the liquid crystal molecules 302 are arranged in parallel to the comb-shaped electrode 303 (FIG. 11A) and, when the electric field E is generated, the liquid crystal molecules 302 are rotated by 90 degrees in the horizontal direction and are arranged in the generation direction of the electric field E (FIG. 11B). Since the FFS type liquid crystal display device has a larger numerical aperture than the IPS type liquid crystal display device, the development thereof is actively progressed (for example, JP-A-2002-296611).
However, the FFS type liquid crystal monitor has the following problems. FIG. 12 is a plan view showing a general example of the shape of an electrode related to the FFS type liquid crystal display device. In the drawing, a plurality of first electrodes 303a extending a vertical direction and a second electrode 303b and a third electrode 303c which are extended in a horizontal direction and are connected to the first electrodes 303a are integrally formed, thereby forming a trapezoidal electrode 303. In an area in which the electrode 303 is not formed, a rectangular slit 306 is formed in plan view.
When a voltage is applied between the electrode 303 and an electrode 304 (not shown), an electric field E denoted by an arrow is generated such that liquid crystal molecules 302 are arranged in an electric field direction. At this time, since the first electrodes 303a and the second electrode 303b are different from each other in the extension direction, the directions of the electric fields generated in the vicinities of the electrodes are different from each other. In other words, the electric field generated from the first electrodes 303a is dominant in an area AR1 in the vicinity of a central portion of the slit 306 and the electric field generated from the second electrode 303b and the third electrode 303c is dominant in areas AR2 in the vicinities of the both ends of the slit 306 in a longitudinal direction. Thus, the directions of the electric fields E are shifted by 90 degrees on the basis of the extension directions of the electrodes in the areas AR1 and AR2. As a result, the area AR1 and AR2 are different from each other in the arrangement direction of the liquid crystal molecules 302 and disclination of the arrangement is generated. The disclination deteriorates light transmissivity, contrast and optical characteristics.
In the existing FFS type device, areas, in which the directions of the electric fields are different from each other by the shape of the electrode, are generated and the arrangement directions of the liquid crystal thereof are different from each other. Thus, the optical characteristics deteriorate.